Effect of La2O3 in Carbon Deposition on Pt/Al2O3 during Methylcyclopentane Reaction
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- 作者：D. Gonzá ; lez ; E. Lima ; N. Martí ; n
- 刊名：Industrial & Engineering Chemistry Research
- 出版年：2007
- 出版时间：June 6, 2007
- 年：2007
- 卷：46
- 期：12
- 页码：4335 - 4340
- 全文大小：127K
- 年卷期：v.46,no.12(June 6, 2007)
- ISSN：1520-5045
文摘
In this work, we have studied the effect of the addition of lanthanum oxide to Pt/Al2O3 catalysts on its catalyticproperties and its resistance to coke deactivation. The catalysts used contained 1.0 wt % in Pt, dispersed onthree different supports: 
-Al2O3 (Pt/A), La2O3 (Pt/L), and a mixture (50:50 wt %) of La2O3--Al2O3 (Pt/AL). All the samples were characterized by X-ray diffraction (XRD), BET analysis, and temperature-programmed reduction (TPR). TPR profiles evidence the presence of an important interaction between Ptand La2O3. The activity and selectivity of the catalysts were evaluated in the hydrogenolysis of methylcyclopentane (MCP) reaction. The specific initial rates showed the following order: Pt/A 
Pt/AL 
Pt/L.Regarding selectivity, the three samples were all alike. The ratios of specific rates, final to initial, were: Pt/A0.68; Pt/AL 0.50; Pt/L 0.52. The amount of carbon deposited on the Pt/AL catalyst was comparable to thaton Pt/A, and both were smaller than the one deposited on Pt/L. The characterization of deactivated samplesby TPO, Fourier transform infrared (FTIR), 27Al MAS (magic-angle spinning) NMR and 13C MAS NMRshowed differences in the coke nature between the samples. The results point out lanthana sites with differencesresponses to carbonaceus residues.
-Al2O3 (Pt/A), La2O3 (Pt/L), and a mixture (50:50 wt %) of La2O3--Al2O3 (Pt/AL). All the samples were characterized by X-ray diffraction (XRD), BET analysis, and temperature-programmed reduction (TPR). TPR profiles evidence the presence of an important interaction between Ptand La2O3. The activity and selectivity of the catalysts were evaluated in the hydrogenolysis of methylcyclopentane (MCP) reaction. The specific initial rates showed the following order: Pt/A Pt/AL Pt/L.Regarding selectivity, the three samples were all alike. The ratios of specific rates, final to initial, were: Pt/A0.68; Pt/AL 0.50; Pt/L 0.52. The amount of carbon deposited on the Pt/AL catalyst was comparable to thaton Pt/A, and both were smaller than the one deposited on Pt/L. The characterization of deactivated samplesby TPO, Fourier transform infrared (FTIR), 27Al MAS (magic-angle spinning) NMR and 13C MAS NMRshowed differences in the coke nature between the samples. The results point out lanthana sites with differencesresponses to carbonaceus residues.